The Few become fewer with every passing year, but the debt we owe our Battle of Britain heroes remains as large as ever.

Yesterday, as the roar of a Spitfire and Hurricane filled the air over London once more, just a handful of the men who flew them so bravely in 1940 were there to hear it.

At exactly 3.52pm Winston Churchill's famous tribute was read out again 70 years on.

"The gratitude of every home in our island, in our empire, and indeed throughout the world... goes out to the British airmen who, undaunted by odds, unwearied in their constant challenge and mortal danger, are turning the tide of the World War by their prowess and by their devotion. Never in the field of human conflict was so much owed by so many to so few."

Those immortal words captured the bravery of the The Few - the RAF pilots whose epic struggle turned the tide of the Second World War. During three-and-a-half months of aerial combat they helped prevent a Nazi invasion by defeating the German Luftwaffe.

Just 100 veterans of RAF Fighter Command are still alive. A handful turned out for a commemoration ceremony in London yesterday, their medals glinting in the afternoon sun.

Most in their 90s, they used sticks or walking frames to take their places outside the Churchill War Rooms. Others were in wheelchairs.

They listened intently as Churchill's famous speech was read out by actor Robert Hardy during the rousing ceremony that left many in tears. It was one of several stirring addresses by Churchill that helped galvanize British resolve in the darkest days of the war.

"It brought it all back. So much was owed to so few, and it is wonderful that some of those brave men are here," said Dame Vera, 93.

Lady Soames, 88, added: "Seventy years ago I was in the House of Commons to hear my father deliver the speech.

"For me it has particular meaning but I find it wonderful that I look around this crowd and for all of us somehow the speech rang a bell."

The crowds waving Union Flags cheered as a Spitfire and a Hurricane fighter - the two key aircraft used during epic air-to-air combat - then swooped over Whitehall. Nigel Rose, now 92, was a newly trained Spitfire pilot battling German bombers over England's south coast. He said: "I don't think one realised that this scrap that we were having would have a startling effect on the progress of events, and possibly help stop the impending invasion."

Wing Commander Tom Neil, 89, a former Hurricane pilot, added: "I'm quite amazed and touched by how many people have turned out today, this is quite moving that we are still remembered in this way."

The Battle of Britain, between July 10 and October 31, 1940, came as Adolf Hitler had Britain in his sights after the evacuation Dunkirk that June. Britain retained naval superiority and Hitler knew that an invasion would be made easier if Germany could establish control of the air zone. The Luftwaffe had the clear advantage - 750 long-range and 250 dive bombers, 600 single-engined and 150 twinengined fighter, compared to the RAF's 600.

But the pilots - average age 22 - defied all odds, assisted by the efforts of the ground crew, observers, plotters and commanders in Operations Headquarters. Out of around 3,000, 544 British and Allies were killed, 422 wounded and 1,547 aircraft destroyed. The Germans had 2,698 casualties and lost 1,887 aircraft.

Churchill's "Few", as they became known, have been celebrated ever since.

Phil Reed, director of Churchill War Rooms, said: "Now part of the general folklore of the battle, the speech is today considered a defining moment of the conflict and one of Churchill's most emotive and stirring pronouncements."